The contention exit allows the resource request, while possibly changing the ownership attributes requested.

The contention exit does not allow the ownership state requested.

The contention exit changes the ownership data of a resource that is currently owned.

The contention exit neither grants nor denies the resource request. The request remains pending on the resource request queue until it is granted, denied, or superseded. (When a pending request from a user on the resource request queue is replaced by a more current request (that is, an ALTER or RELEASE request) from that user, the previous request is said to be superseded.)

The contention exit may choose to inform one or more users that contention exists for a resource it owns by executing the notify exit of those users. The notify exit receives as input a notify exit parameter list (NEPL) representing the current resource request queue. Based on its evaluation of the resource request queue, the notify exit may choose to take actions to alleviate the contention. The IXLSYNCH service provides the mechanism by which the notify exit of a connected user may synchronously update or release its interest in a resource. After the specified notify exits have been executed, the resultant resource request queue (containing any changes made by the notify exits) is presented to the contention exit. Through the use of the notify exit, an application can implement protocols that allow owners and requestors of a resource to negotiate for ownership.